Re: [PATCH] gpio: pl061: Warn when IRQ line has not been configured

[Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>]

śr., 4 mar 2020 o 15:58 Alexander Sverdlin
<alexander.sverdlin@xxxxxxxxx> napisał(a):
>
> Hi!
>
> On 04/03/2020 15:21, Bartosz Golaszewski wrote:
> > wt., 3 mar 2020 o 10:29 Alexander A Sverdlin
> > <alexander.sverdlin@xxxxxxxxx> napisał(a):
> >> From: Alexander Sverdlin <alexander.sverdlin@xxxxxxxxx>
> >>
> >> Existing (irq < 0) condition is always false because adev->irq has unsigned
> >> type and contains 0 in case of failed irq_of_parse_and_map(). Up to now all
> >> the mapping errors were silently ignored.
> >>
> >> Seems that repairing this check would be backwards-incompatible and might
> >> break the probe() for the implementations without IRQ support. Therefore
> >> warn the user instead.
> >>
> >> Signed-off-by: Alexander Sverdlin <alexander.sverdlin@xxxxxxxxx>
> >> ---
> >>  drivers/gpio/gpio-pl061.c | 6 ++----
> >>  1 file changed, 2 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/drivers/gpio/gpio-pl061.c b/drivers/gpio/gpio-pl061.c
> >> index 5df7782..3439120 100644
> >> --- a/drivers/gpio/gpio-pl061.c
> >> +++ b/drivers/gpio/gpio-pl061.c
> >> @@ -326,10 +326,8 @@ static int pl061_probe(struct amba_device *adev, const struct amba_id *id)
> >>
> >>         writeb(0, pl061->base + GPIOIE); /* disable irqs */
> >>         irq = adev->irq[0];
> >> -       if (irq < 0) {
> >> -               dev_err(&adev->dev, "invalid IRQ\n");
> >> -               return -ENODEV;
> >> -       }
> >> +       if (!irq)
> >> +               dev_warn(&adev->dev, "IRQ support disabled\n");
> >>         pl061->parent_irq = irq;
> >>
> >>         girq = &pl061->gc.irq;
> >> --
> >> 2.4.6
> >>
> > What happens later on if irq == 0? Does irq_set_irq_wake() fail?
>
> Yes, would fail if IRQs would be requested from PL061:
>
> int irq_set_irq_wake(unsigned int irq, unsigned int on)
> {
>         unsigned long flags;
>         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
>         int ret = 0;
>
>         if (!desc)
>                 return -EINVAL;
>
>
> --
> Best regards,
> Alexander Sverdlin.

Ok, I'll go ahead and queue this then.

Thanks!
Bartosz